The ultimate objective of this research program is to improve prostate cancer diagnosis and treatment via a novel ultrasonic tissue-typing technique. Its clinical significance derives from the fact that prostate cancer is the most common cancer and the second leading cause of cancer death in American men. The proposed research will develop a reliable non-invasive means of identifying and localizing cancerous regions within the prostate gland using an ultrasonic tissue-typing (UTT) technique based on 2-D spectrum analysis. Ultrasound data from 100 prostate cancer patients will be analyzed to create 3-D cancer maps. The UTT 3-D cancer mapping will be incorporated into image guided dose escalation in prostate brachytherapy (seed implant). The specific aims are: 1) To develop and refine a novel UTT technique, specifically 2-D spectrum analysis, in order to identify cancerous regions within the prostate gland;2) To evaluate the accuracy of this 2-D spectrum UTT technique;3) To generate 3-D cancer map with the locations and volumes of tumor foci, and incorporate the cancer map into image-guided dose escalation of prostate cancer brachytherapy;and 4) To evaluate the feasibility and efficacy of the UTT image-guided treatment in terms of better tumor control and reduced radiation toxicity. The candidate's career development activities and research plan capitalize on the resources of Columbia University to aid in achieving her long-term goal of becoming an independent investigator in ultrasonic tissue-typing imaging and imaging guided radiation therapy. In the training plan, she will take courses, attend seminars and receive expert mentorship in key areas, including prostate cancer, ultrasonic imaging, radiation physics, and ethical research conduct.